/Engine/Plugins/Runtime/GameplayAbilities/Source/GameplayAbilities/Public/GameplayAbilitySpecHandle.h
This file exists in addition so that GameplayEffect.h can useFGameplayAbilitySpecwithout having to include GameplayAbilityTypes.h which has depancies on GameplayEffect.hHandle that points to a specific granted ability. These are globally unique
[USTRUCT](Programming/UnrealArchitecture/Reference/Structs)([BlueprintType](Programming/UnrealArchitecture/Reference/Structs/Specifiers/BlueprintType)) struct FGameplayAbilitySpecHandle